=====================
PyGreSQL Installation
=====================

.. sectnum::
.. contents:: Contents


General
=======

You must first have installed Python and PostgreSQL on your system.
If you want to access remote database only, you don't need to install
the full PostgreSQL server, but only the C interface (libpq). If you
are on Windows, make sure that the directory with libpq.dll is in your
``PATH`` environment variable.

The current version of PyGreSQL has been tested with Python 2.5 and
PostGreSQL 8.3. Older version should work as well, but you will need
at least Python 2.3 and PostgreSQL 7.4.

PyGreSQL will be installed as three modules, a dynamic module called
_pg.pyd, and two pure Python wrapper modules called pg.py and pgdb.py.
All three files will be installed directly into the Python site-packages
directory. To uninstall PyGreSQL, simply remove these three files again.


Installing from a Binary Distribution
=====================================

This is the easiest way to install PyGreSQL.

You can currently download PyGreSQL as Linux RPM, NetBSD package and Windows
installer. Make sure the required Python version of the binary package matches
the Python version you have installed.

Install the package as usual on your system.

Note that the documentation is currently only included in the source package.


Installing from Source
======================

If you want to install PyGreSQL from Source, or there is no binary
package available for your platform, follow these instructions.

Make sure the Python header files and PostgreSQL client and server header
files are installed. These come usually with the "devel" packages on Unix
systems and the installer executables on Windows systems.

If you are using a precompiled PostgreSQL, you will also need the pg_config
tool. This is usually also part of the "devel" package on Unix, and will be
installed as part of the database server feature on Windows systems.

Building and installing with Distutils
--------------------------------------

You can build and install PyGreSQL using
`Distutils <http://docs.python.org/install/>`_.

Download and unpack the PyGreSQL source tarball if you haven't already done so.

Type the following commands to build and install PyGreSQL::

    python setup.py build
    python setup.py install

If you are using `MinGW <http://www.mingw.org>`_ to build PyGreSQL under
Microsoft Windows, please note that Python newer version 2.3 is using msvcr71
instead of msvcrt as its common runtime library. You can allow for that by
editing the file ``%MinGWpath%/lib/gcc/%MinGWversion%/specs`` and changing
the entry that reads ``-lmsvcrt`` to ``-lmsvcr71``. You may also need to copy
``libpq.lib`` to ``libpq.a`` in the PostgreSQL ``lib`` directory. Then use
the following command to build and install PyGreSQL::

    python setup.py build -c mingw32 install

Now you should be ready to use PyGreSQL.

Compiling Manually
------------------

The source file for compiling the dynamic module is called pgmodule.c.
You have two options. You can compile PyGreSQL as a stand-alone module
or you can build it into the Python interpreter.

Stand-Alone
-----------

* In the directory containing ``pgmodule.c``, run the following command::

    cc -fpic -shared -o _pg.so -I$PYINC -I$PGINC -I$PSINC -L$PGLIB -lpq pgmodule.c

  where you have to set::

    PYINC = path to the Python include files
            (usually something like /usr/include/python)
    PGINC = path to the PostgreSQL client include files
            (something like /usr/include/pgsql or /usr/include/postgresql)
    PSINC = path to the PostgreSQL server include files
            (like /usr/include/pgsql/server or /usr/include/postgresql/server)
    PGLIB = path to the PostgreSQL object code libraries (usually /usr/lib)

  If you are not sure about the above paths, try something like::

    PYINC=`find /usr -name Python.h`
    PGINC=`find /usr -name libpq-fe.h`
    PSINC=`find /usr -name postgres.h`
    PGLIB=`find /usr -name libpq.so`

  If you have the ``pg_config`` tool installed, you can set::

    PGINC=`pg_config --includedir`
    PSINC=`pg_config --includedir-server`
    PGLIB=`pg_config --libdir`

  Some options may be added to this line::

    -DNO_DEF_VAR   no default variables support
    -DNO_DIRECT    no direct access methods
    -DNO_LARGE     no large object support
    -DNO_PQSOCKET  if running an older PostgreSQL

  Define ``NO_PQSOCKET`` if you are using a version of PostgreSQL before 6.4
  that does not have the PQsocket function. The other options will be
  described in the next sections.

  On some systems you may need to include ``-lcrypt`` in the list of libraries
  to make it compile.

* Test the new module. Something like the following should work::

    $ python

    >>> import _pg
    >>> db = _pg.connect('thilo','localhost')
    >>> db.query("INSERT INTO test VALUES ('ping','pong')")
    18304
    >>> db.query("SELECT * FROM test")
    eins|zwei
    ----+----
    ping|pong
    (1 row)

* Finally, move the ``_pg.so``, ``pg.py``, and ``pgdb.py`` to a directory in
  your ``PYTHONPATH``. A good place would be ``/usr/lib/python/site-packages``
  if your Python modules are in ``/usr/lib/python``.

Built-in to Python interpreter
------------------------------

* Find the directory where your ``Setup`` file lives (usually in the ``Modules``
  subdirectory) in the Python source hierarchy and copy or symlink the
  ``pgmodule.c`` file there.

* Add the following line to your 'Setup' file::

    _pg  pgmodule.c -I$PGINC -I$PSINC -L$PGLIB -lpq

  where::

    PGINC = path to the PostgreSQL client include files (see above)
    PSINC = path to the PostgreSQL server include files (see above)
    PGLIB = path to the PostgreSQL object code libraries (see above)

  Some options may be added to this line::

    -DNO_DEF_VAR   no default variables support
    -DNO_DIRECT    no direct access methods
    -DNO_LARGE     no large object support
    -DNO_PQSOCKET  if running an older PostgreSQL (see above)

  On some systems you may need to include ``-lcrypt`` in the list of libraries
  to make it compile.

* If you want a shared module, make sure that the ``shared`` keyword is
  uncommented and add the above line below it. You used to need to install
  your shared modules with ``make sharedinstall`` but this no longer seems
  to be true.

* Copy ``pg.py`` to the lib directory where the rest of your modules are.
  For example, that's ``/usr/local/lib/Python`` on my system.

* Rebuild Python from the root directory of the Python source hierarchy by
  running ``make -f Makefile.pre.in boot`` and ``make && make install``.

* For more details read the documentation at the top of ``Makefile.pre.in``.
